Method and apparatus for finishing taper articles



March M 1924. 35,486,344

w. E. HOKE METHOD AND PPARATUS FOR FINISHING TAPER ARTICLES Filed Aug. 10 1920 2 Sheets-Sheet 2 @13 @7W aww @M www@ Fatentedl `lifter. lill, lge.

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WILLIAM E. HOKE, BALTIMORE, MARYLAND.

METHD Application :Bled August 10, 1920. Serial No. 402,603.

To all fwlwm t 'ma/y concern:

Be itfknown that l, Winnaar E. Home, a citizenof the gUnited States, residing' at 2008 North Charles Street, Baltimorain the county of Baltimore City and State of Maryland, have invnted certain new and useful improvements in Methods and Apparatus for Finishing Taper Articles, of which the following is a specification.

My invention relates to improvements 1n the method and apparatus for finishing tap per. articles, such as twist drills, taper mandrels, and the like.

In the manufacture of twist drills, the usual method of procedure is to form the chip grooves or tintes in any suitable manner, as by'milling out of a solid blank. rlhe thus partially formed tool is then hardened which operation has a tendency to warp or bendthe drills. The drill must, if warped or bent, then be straightened; and the spiral lands are then ground slightly tapered, the diameter of the pointed portion ci the drill beiri vexy slightly larger than that of the sha' en ,this grinding o eration requiring special machinery an must be performed on each individual drill.

lt is the object ci my invention to greatly simpli and to lessen the number of operations w in twist drills. This ,object ll attain b su jecting a. large number ofhardened dri l blanks to a simultaneous lapping by which they are ground to the desired taper form and during the same operation straightened' and reduced to the proper diameter.

rlhe invention will be readily understood from the accompanying more or less diagrammatic drawings in which- Fig. 1 is an end elevation, the work-holders being shown in section.

Fig. 2 is a plan of the machine with the upper lap removed.

Fig. 3 is' a detail of the means for connecting the several work-holders.

Fig. 4 is a plan view of the work-holder, showing the drill-blanks located in theopenings, and

Fig. 5 is a plan, looking down on the npper lap.

In carrying out my invention l use at faced lapping blocks, one oi which, A, ma be stationary, while the other, B, is movab e relatively to A. Both blocks may, however, be reciprocated in opposite directions.

'.lhe working faces of the blocks, A and A permit ich have4 to be performed in inish- B, are charged with suitable abrasive material in the usual way, andthe lapping operation is carried out in the usual manner, oil or other liquid being used as a lubricant.

For reciprocating the block B, any suitable mechanism ma be used, such as a connecting rod 1), an crank E, driven by a ulle F. The connecting rod D is so connected to the block B, as to permit of free movement of this block; and for this purose, a universal joint connection may be used. The block B is held against transverse movement by rollers G, supported on brackets H supported in any suitable manner. Between the two work-holders, each of which may consist of a thin metal plate slightly less in thickness than the diameter oi the finished drills, these plates having a series of apertures therein preferably of sucient width to contain several drills, and of a length just suiicient to insertion and withdrawal of the drills. 'llhese apertures are preferably arranged diagonally and are oppositely in- -clined in adjacent work-holders to counteract a tendency to side thrust. rlhe several work-holders are each other by any suitable means, such as hooks, J, "fitting into corresponding openings, K, so that as each Awork-holder is inserted at the front end of the machine, it can be attached to one already in the machine, vvhile the work-holder containing iinished drills can he readily detached from its neighbor which is to remain in the machine.

The operation of the machine is commenced by locating one or two of the workholders between the laps, and then successively attaching fresh work-holders at the front and removing the work-holders containing the nshed 'drills at the back of the machine.

The drill blanks are taken in the rough, as they come from the hardening operation; lilled into the work-holders; subjected to the lappin operation in the machine until they are re uced to the proper diameter, and are delivered from the machine -in finished condition.

When the sequence of operation has once been established it will be apparent that the upper lajl will be inclined in the direction of the lengt of the drills from front to back of the machine, as indicated in Fig. 1, since the unstraightened and unground drills located in the holders at the trent of the machine are lapping blocks are located detachably connected to lll@ of slightly larger diameter than the finished drills located at the back of the machine.

As a result of this operation the drills are given the desired ta er, are perfectlyv straightened and the lan s highly polished. The mechanism required is of the simplest character and no skilled operator is required for its operation. Further, a large number ofv drills can be simultaneously treated, thereby greatlyreducing the cost of manufacture.

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My invention is of particular importance in that it enables drills and like tapered ar` l the cavities in the work-holders. Because of the inclination of these, cavities, the drills do not merely roll 'between thelaps, but

their surfaces are given an additional movement relative to the successive portions of the engaging surfaces ofthe laps, whereby a grinding action is-produced.

Ubviously the apparatus may take many' varied forms, the particular form shown being illustrative o the general type of machlne which I consider to be adapted for carrying out the method described.

Thus, the number of work-holders may be varied. to thereby control the conditions of operatlon. With a smaller number of trays I the taper imparted tothe drills will be greater. With a larger number of trays and the ta er will be less.

rlhis wil be apparent from the fact that the working sur ace of the upper lap is inclined to the working surface of the lower releases lap, while the drills are inclined to the direction of relative movement of the laps.

The inclination of the upper lap surface is due tothe fact that at the front it is resting on rough or oversize drills while at the back it is resting on finished drills of less diameter. fBy varying the distance from front to back of the machine, asby inserting additional work-holders, the angle of inclination can be varied at will.

ll claim 1. The method'of finishing twistfdrills or the like Which'consists in subjecting a multilicity of such articles to a simultaneous apping between laps, one of which is freely floating, to which laps a relative movement of one lap with reference to the other is imparted, the articles to be lapped being arranged with their longitudinal axes at an angle to the direction of relative movement of the laps.

2. The method as claimed in claim 1, in which the drills are free to rotate on their axes whileheld against axially longitudinal movement.

3. The method as claimed in claim 2, in j which groups of drills are caused to move in succession between the laps transversely to thedirection of relative movement of the laps.

A11 apparatus for nishin twist drills and the like comprising two apping sur-v.

faces one of which is freely floating, means for imparting relative movement thereto, a series of holders located betweensaid surfaces each of less thickness than the iin- -ished drill, said holders having drill-receiving apertures therein arranged at an angle to the direction of relative movement j of the laps.

5. An apparatus as claimed in claim 4in which the apertures in adjacent holders are inclined in opposite directions.

. ln testimony whereof, l aiiix. my signature.

MAM n; HOKE. 

